The prison cells

The main difference between cell types are those, that have windows and those that don't--dark cells for solitary confinement. Even though the majority of cells have windows, these could not be opened. They were made of thick glass bricks that don't allow to see anything outside, no sky, no clouds, no greenery, nothing. It was part of the fiendish arsenal to break the inmates.

The dark cells section in the basement was called the "U-Boat" by the inmates and in fact it really appears to be like that. Down there inmates got water-torture, were forced to stand all day. Even the beds were too short to stretch out to get some sleep. Then there was the rule of "both hand always have to be visible". The inmates were under constant observation, day and night. So, if an inmate turns to one side during sleep, his hands weren't visible anymore. The cell door gets banged at by the guard, yelling "hands visible!!!". A good nights sleep? Forget it.

There were so many more fiendish methods used to break inmates...

I strongly recommend to take a tour through the complex with one of the guides. Many of them have been inmates and can tell you a lot about life and death in this prison.